JP2013039638A - Carrying method and robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem with a conventional robot, wherein operations are liable to stagnate easily after gripping a workpiece.SOLUTION: A carrying method includes: a gripping step S3 of holding the workpiece in a holding part for holding the workpiece; a holding power confirmation step S4 of driving the holding part while holding the workpiece by the holding part; a holding state recognition step S5 of recognizing a holding state of the workpiece by the holding part, based on the results obtained by detecting a behavior of the holding part when the holding part is driven by the holding power confirmation step S4 with an inertial sensor; and a carrying step S6 of carrying the workpiece held at the holding part by driving the holding part after the holding state recognition step S5. The method is characterized by controlling a carrying speed for carrying the workpiece according to the holding state recognized by the holding state recognition step S5 in the carrying step S6.

Description

  The present invention relates to a transfer method, a robot, and the like.

  Conventionally, in a robot having a hand for gripping a workpiece, visual feedback control has been utilized for controlling the hand when the hand grips the workpiece (see, for example, Patent Document 1).

JP 2009-78312 A

In such visual feedback control, the robot hand is controlled to a posture associated with the posture of the workpiece represented in an image obtained by imaging the workpiece with the imaging unit. As a result, it is possible to save the time and effort required to calculate the target position and orientation of the robot hand, so that it is possible to easily shorten the time required for controlling the robot.
However, for example, in a workpiece conveyed by a belt conveyor or the like, the position and posture of the workpiece with respect to the robot change with time, so the posture of the workpiece when captured by the imaging unit is different from the posture of the workpiece immediately before the hand is gripped. May end up. In such a case, the hand unit grips the workpiece that has changed to a posture different from the posture at the time when the image is picked up by the image pickup unit. In such a case, after the hand grips the work, the position and posture of the work with respect to the hand may be displaced, or the work may fall off the hand. When such a thing occurs, the work after gripping the workpiece tends to be delayed.
In other words, the conventional robot has a problem that the work after gripping the workpiece tends to be delayed.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A holding step for holding the workpiece in a holding portion for holding the workpiece, a driving step for driving the holding portion in a state where the workpiece is held in the holding portion, and the holding portion in the driving step A holding state recognition step for recognizing the holding state of the workpiece by the holding unit based on a result of detecting the behavior of the holding unit when the holding unit is driven, and after the holding state recognition step, the holding unit A conveying step of conveying the workpiece held by the holding unit, and in the conveying step, the workpiece is conveyed according to the holding state recognized in the holding state recognizing step. A conveyance method characterized by controlling a conveyance speed to be performed.

In the conveyance method of this application example, in the holding state recognition step, the holding state of the workpiece by the holding unit is recognized based on the result of detecting the behavior of the holding unit when the holding unit is driven in the driving step by the inertia sensor.
Here, for example, the behavior when the holding unit is driven is different between the case where the workpiece is held by the holding unit in an unstable state and the case where the workpiece is held by the holding unit in a stable state. In this transport method, the unstable holding state and the stable holding state can be determined based on the result of detecting the behavior of the holding portion by the inertia sensor in the holding state recognition step.
And since the conveyance speed of the workpiece | work in a conveyance step is controlled according to the holding | maintenance state of the workpiece | work recognized at the holding | maintenance state recognition step, the conveyance according to the holding | maintenance state of a workpiece | work can be performed. For example, when the workpiece is held in the holding portion in an unstable state, it is easy to suppress the position and posture of the workpiece with respect to the holding portion during the conveyance process, and the workpiece from falling off the holding portion. can do.
As a result, the work after the transport step including the transport step can be made difficult to be delayed.

  Application Example 2 In the transport method described above, in the holding state recognition step, the holding state is determined based on a result of detecting the behavior of the holding unit when the driving of the holding unit is stopped by the inertial sensor. Recognizing the transfer method.

  In this application example, since the behavior of the holding unit when the driving of the holding unit is stopped is detected by the inertial sensor, the behavior of the holding unit when the driving of the holding unit is stopped can be detected. Accordingly, it is possible to easily distinguish between a stable holding state and an unstable holding state based on the behavior of the holding unit.

  Application Example 3 In the transport method described above, the inertial sensor is an angular velocity sensor that detects an angular velocity, and in the holding state recognition step, the angular velocity sensor uses the angular velocity of the holding unit as the behavior of the holding unit. A conveying method characterized by detecting.

  In this application example, the behavior of the holding unit can be detected by detecting the angular velocity of the holding unit with an angular velocity sensor. And based on the result of the detected angular velocity, the holding | maintenance state of the workpiece | work by a holding | maintenance part can be recognized.

  Application Example 4 In the transport method described above, in the driving step, the holding unit is swung by driving a swinging device that swings the holding unit.

  In this application example, when the holding unit is swung by driving the swinging device, a centrifugal force can be applied to the work, so that the work held by the holding unit in an unstable state is removed from the holding unit. It can be made easy to drop off. For this reason, it can be made easy to avoid moving to a conveyance step in the unstable holding state that the work falls off from the holding part.

  Application Example 5 In the transport method described above, in the driving step, the holding unit is swung in a direction including at least a direction in which gravity acts.

  In this application example, the centrifugal force acting on the workpiece can include the centrifugal force acting in the same direction as the direction in which the gravity acts, so that the centrifugal force and the gravity can act on the workpiece. Thereby, the workpiece | work currently hold | maintained at the holding | maintenance part in the unstable state can be made still easier to drop from a holding | maintenance part.

  Application Example 6 A holding unit that holds a workpiece, an inertial sensor provided in the holding unit, and a control unit that controls driving of the holding unit, and the control unit includes Holding the workpiece, detecting the behavior of the holding unit when the holding unit is driven by the inertial sensor, recognizing the holding state of the workpiece by the holding unit based on the detection result of the inertial sensor, A robot characterized by controlling a conveyance speed in conveyance of the workpiece according to a holding state.

The robot of this application example includes a holding unit that holds a workpiece, an inertial sensor provided in the holding unit, and a control unit that controls driving of the holding unit.
The control unit holds the workpiece in the holding unit, detects the behavior of the holding unit when the holding unit is driven, and recognizes the holding state of the workpiece by the holding unit based on the result detected by the inertia sensor, The workpiece conveyance speed is controlled according to the holding state.
Here, for example, the behavior when the holding unit is driven is different between the case where the workpiece is held by the holding unit in an unstable state and the case where the workpiece is held by the holding unit in a stable state. For this reason, an unstable holding state and a stable holding state can be distinguished based on the result of detecting the behavior of the holding portion with the inertial sensor.
The control unit controls the conveyance speed of the workpiece according to the recognized holding state of the workpiece. Thereby, the conveyance according to the holding | maintenance state of a workpiece | work can be performed. For example, when the workpiece is held in the holding portion in an unstable state, it is easy to suppress the position and posture of the workpiece with respect to the holding portion during the conveyance process, and the workpiece from falling off the holding portion. can do.
As a result, it is possible to make it difficult to delay the subsequent work including the conveyance of the work.

  Application Example 7 In the robot described above, the robot includes a swinging device that swings the holding unit, and the control unit is configured to rotate the holding unit when the holding unit is swung by the swinging device. Detecting a behavior with the inertial sensor, recognizing a holding state of the workpiece by the holding unit based on a result detected by the inertial sensor, and controlling a conveyance speed in conveying the workpiece according to the holding state; Robot characterized by.

  In this application example, when the control unit swings the holding unit on the swinging device, a centrifugal force can be applied to the workpiece, so that the workpiece held by the holding unit in an unstable state is dropped from the holding unit. It can be made easy. For this reason, it can be made easy to avoid shifting to the conveyance of the workpiece in an unstable holding state such that the workpiece is dropped from the holding portion.

  Application Example 8 In the above robot, the control unit swings the holding unit in a direction including at least a direction in which gravity acts.

  In this application example, the centrifugal force acting on the workpiece can include the centrifugal force acting in the same direction as the direction in which the gravity acts, so that the centrifugal force and the gravity can act on the workpiece. Thereby, the workpiece | work currently hold | maintained at the holding | maintenance part in the unstable state can be made still easier to drop from a holding | maintenance part.

FIG. 2 is an external view illustrating a schematic configuration of a robot according to the present embodiment. The enlarged view of the A section in FIG.1 (b). 1 is a block diagram showing a schematic configuration of a robot in the present embodiment. The figure explaining the schematic structure of the conveyance system in this embodiment. The figure which shows the flow of the conveying method in the conveying system in this embodiment. The figure explaining the operation | movement in the retention strength confirmation step in this embodiment. The example of the behavior of the hand part detected by the holding power confirmation step in this embodiment.

Embodiments will be described with reference to the drawings. In addition, in each drawing, in order to make each structure the size which can be recognized, the structure and the scale of a member may differ.
As shown in FIG. 1A, which is a perspective view showing a schematic configuration, the robot 1 in the embodiment includes a base 3, a support base 5, an arm device 7, a hand device 9, and an imaging device 11. Have.
The base 3 extends along the XY plane defined by the X direction and the Y direction. The direction orthogonal to the XY plane is defined as the Z direction.
The support base 5 is placed on the base 3. The support base 5 supports the arm device 7.
The arm device 7 includes a first arm 21 and a second arm 23.

As shown in FIG. 1B, which is a front view of the robot 1, one end side of the first arm 21 is supported by the support base 5 via a joint portion 25. The first arm 21 is configured to be rotatable about a rotation shaft 26 by a joint portion 25.
On the other end side of the first arm 21, one end side of the second arm 23 is supported via a joint portion 27. The second arm 23 is configured to be rotatable about a rotation shaft 29 by a joint portion 27.
The arm device 7 has a motor (not shown) that generates power for rotating the first arm 21. The arm device 7 also has a motor (not shown) that generates power for rotating the second arm 23.
The hand device 9 is provided on the other end side of the second arm 23 opposite to the joint portion 27 side.

As shown in FIG. 2, which is an enlarged view of part A in FIG. And have. The hand device 9 is supported by the second arm 23 via the lifting device 33.
The elevating device 33 can elevate the elevating shaft 31 along the Z direction. The lifting device 33 has a power source (not shown) that generates power for moving the lifting shaft 31 up and down. The power from the power source is transmitted to the lifting shaft 31 via a lifting mechanism (not shown). Thereby, the raising / lowering axis | shaft 31 can be raised / lowered along a Z direction. In the present embodiment, a motor (not shown) is employed as a power source for driving the elevating shaft 31.
A hand portion 39 is supported on the lower end side in the Z direction of the elevating shaft 31 via a swing device 35 and a rotation device 37.

The hand part 39 has a pair of finger parts 43. The pair of finger parts 43 are configured to be able to approach and move away from each other. Further, the hand unit 39 has a power source that generates power for driving the pair of finger units 43. The power from this power source is transmitted to the pair of finger parts 43 via a transmission mechanism (not shown). In the present embodiment, a motor (not shown) is employed as a power source for driving the pair of finger portions 43.
Thereby, in the robot 1, the workpiece W can be held between the pair of finger portions 43. Then, the work W can be transported by driving the arm device 7 in a state where the work W is sandwiched between the pair of finger portions 43. In the following, an operation in which the pair of finger parts 43 hold the work W may be expressed as the hand part 39 grips the work W, or may be expressed as the hand part 39 grips the work W.
The rotating device 37 is interposed between the hand unit 39 and the elevating shaft 31 and can rotate the hand unit 39 around the rotating shaft 45 shown in FIG.

The oscillating device 35 is interposed between the rotating device 37 and the elevating shaft 31 and can oscillate the hand portion 39 in the R direction in FIG. 2 with the joint portion 47 as a fulcrum. The joint 47 can be compared to a wrist. And the hand part 39 can perform a swing operation | movement (swing | rocking) by using the joint part as a wrist as a fulcrum.
The swing device 35 includes a motor (not shown) that generates power for swinging the hand unit 39. The rotating device 37 has a motor (not shown) that generates power for rotating the hand unit 39.

As shown in FIG. 2, the hand unit 39 is provided with an angular velocity sensor 51 which is one of inertia sensors. The angular velocity sensor 51 detects an angular velocity in swinging (swinging motion) of the hand portion 39 with the joint portion 47 as a fulcrum. As the angular velocity sensor 51, for example, a gyroscope such as a rotary gyroscope, a vibration gyroscope, a gas gyroscope, or a ring laser gyro can be employed. In the present embodiment, a vibrator-type gyroscope belonging to the vibration-type gyroscope is employed.
The imaging device 11 is supported by a support 55 provided on the base 3 and a beam portion 57 supported by the support 55. The imaging device 11 is provided independently of the arm device 7 and the hand device 9, that is, separately from the arm device 7 and the hand device 9. For this reason, the direction and position of the optical axis of the imaging device 11 are not changed by the operation of the arm device 7 or the hand device 9.
The imaging device 11 has an imaging element. The imaging device 11 images the workpiece W that the hand unit 39 should grasp. In the robot 1, the posture of the workpiece W is recognized based on the result of the imaging device 11 imaging the workpiece W. In addition, as an image pick-up element, elements, such as CCD (Charge Coupled Device), can be employ | adopted, for example.

As shown in FIG. 3, the robot 1 includes a control unit 61 that controls the operation of each of the above components. The control unit 61 includes a CPU (Central Processing Unit) 63, a drive control unit 65, and a memory unit 67. The drive control unit 65 and the memory unit 67 are connected to the CPU 63 via the bus 69.
The robot 1 includes a motor 71, a motor 73, a motor 75, a motor 77, a motor 79, and a motor 81. The motor 71, the motor 73, the motor 75, the motor 77, the motor 79, and the motor 81 are connected to the control unit 61 via an input / output interface 83 and a bus 69, respectively.

The motor 71 generates power for rotating the first arm 21.
The motor 73 generates power for rotating the second arm 23.
The motor 75 generates power for moving the lifting shaft 31 up and down.
The motor 77 generates power for driving the rocking device 35. The hand unit 39 can be swung by the power from the motor 77.
The motor 79 generates power for driving the rotating device 37. The hand unit 39 can be rotated by the power from the motor 79.
The motor 81 generates power for driving the pair of finger portions 43.
The imaging device 11 and the angular velocity sensor 51 are also connected to the control unit 61 via the input / output interface 83 and the bus 69, respectively.

The CPU 63 performs various arithmetic processes as a processor. The drive control unit 65 controls driving of each component. The memory unit 67 includes a RAM (Random Access Memory), a ROM (Read Only Memory), and the like. In the memory unit 67, an area for storing program software 84 in which a control procedure of the operation in the robot 1 is described, a data expansion unit 85 that is an area for temporarily expanding various data, and the like are set. Examples of data developed in the data development unit 85 include recording data indicating a pattern to be drawn, program data such as recording processing, and the like.
The memory unit 67 is also provided with an area for storing posture image data 87 and an area for storing hand posture information 89. Details of the posture image data 87 and the hand posture information 89 will be described later.
The drive control unit 65 includes a motor control unit 91, an imaging control unit 93, and a sensor control unit 95.

The motor control unit 91 individually controls the motor 71, the motor 73, the motor 75, the motor 77, the motor 79, and the motor 81 based on a command from the CPU 63.
The imaging control unit 93 controls the imaging device 11 based on a command from the CPU 63.
The sensor control unit 95 controls the angular velocity sensor 51 based on a command from the CPU 63.
Here, the imaging control unit 93 causes the imaging device 11 to image the workpiece W based on a command from the CPU 63. The imaging result obtained by imaging the workpiece W by the imaging device 11 is output to the CPU 63 of the control unit 61. In the control unit 61, the posture of the workpiece W is recognized based on the imaging result from the imaging device 11.
As described above, the posture image data 87 is stored in the memory unit 67. The posture image data 87 is composed of a plurality of image data indicating all postures of the workpiece W. In the posture image data 87, every posture of the workpiece W is written as image data.

The hand posture information 89 stored in the memory unit 67 is information regarding the posture that the hand unit 39 should take when the workpiece W is gripped. The hand posture information 89 describes the posture that the hand unit 39 should take in correspondence with all postures of the workpiece W. In other words, the hand posture information 89 is associated with each piece of posture image data 87 in relation to the posture to be taken when the hand unit 39 grips the workpiece W.
Then, the CPU 63 collates the imaging result from the imaging device 11 with the plurality of attitude image data 87 and extracts the attitude image data 87 that most closely approximates the imaging result from the plurality of attitude image data 87.

  Next, the CPU 63 outputs drive commands for the motor 71, the motor 73, the motor 75, the motor 77, and the motor 79 to the motor control unit 91 based on the hand posture information 89 associated with the extracted posture image data 87. To do. The motor control unit 91 individually controls driving of the motor 71, the motor 73, the motor 75, the motor 77, and the motor 79 based on a command from the CPU 63. Thereby, the attitude | position of the hand part 39 is controlled. As a result, the hand unit 39 is controlled to a posture to be taken when the workpiece W is grasped.

Then, the CPU 63 outputs a drive command for the motor 81 to the motor control unit 91. The motor control unit 91 controls the drive of the motor 81 based on a command from the CPU 63 to hold the workpiece W between the pair of finger units 43.
As described above, in the robot 1, the posture of the hand unit 39 is based on the hand posture information 89 associated with the posture image data 87 that most closely approximates the imaging result based on the imaging result of the workpiece W by the imaging device 11. Therefore, it is possible to reduce the arithmetic processing related to posture control. As a result, the time required for the gripping operation of the workpiece W by the hand unit 39 can be reduced.

A method for conveying the workpiece W using the robot 1 will be described.
Here, a method for conveying the workpiece W transported by the conveyor from the conveyor to another place will be described as an example.
As shown in FIG. 4, the transport system 10 to which this transport method can be applied includes a robot 1, a conveyor 101, a feeder 103, and a conveyor 105. In FIG. 4, the swing device 35, the rotation device 37, the hand unit 39, and the imaging device 11 are illustrated in the configuration of the robot 1 for easy understanding of the configuration.

The conveyor 101 includes a pair of rollers 107a and 107b that are arranged with a gap therebetween, and an endless belt 109 that spans between the pair of rollers 107a and 107b. In the conveyor 101, the endless belt 109 can be rotationally driven by driving the roller 107b.
The feeder 103 is a device that supplies the workpiece W to the conveyor 101. The feeder 103 includes a storage unit 111 that can store a plurality of workpieces W, and a discharge port 113 that discharges the workpieces W stored in the storage unit 111 one by one. The work W discharged from the discharge port 113 is supplied onto the endless belt 109 of the conveyor 101. The workpiece W supplied from the feeder 103 to the conveyor 101 is placed on the endless belt 109. In this state, by rotating and driving the endless belt 109, the workpiece W on the endless belt 109 is transported from the roller 107a to the roller 107b along the transport direction D in which the rollers 107a and 107b are arranged. Can be transported.

The conveyor 105 is provided on the downstream side of the conveyor 101 in the transport direction D of the workpiece W by the conveyor 101. The conveyor 105 includes a pair of rollers 117 that are arranged with a gap therebetween, and an endless belt 119 that spans the pair of rollers 117. In the conveyor 105, the endless belt 119 can be rotationally driven by driving the roller 117.
On the endless belt 119 of the conveyor 105, the workpiece W that the robot 1 cannot grasp in the conveyor 101 is supplied. The workpiece W supplied onto the endless belt 119 is returned to the accommodating portion 111 of the feeder 103. That is, the workpiece W that the robot 1 cannot grasp on the conveyor 101 is collected by the feeder 103 via the conveyor 105.

The imaging device 11 is arranged at a position facing the workpiece W on the endless belt 109 in the transport path of the conveyor 101.
In the transport route of the conveyor 101, the hand unit 39 is located on the downstream side of the position where the imaging device 11 is disposed.
As shown in FIG. 5, the transport method in the transport system 10 having the above configuration includes an imaging step S1, an attitude control step S2, a gripping step S3, a holding force confirmation step S4, a holding state recognition step S5, Transport step S6.
In the imaging step S <b> 1, the imaging device 11 images the work W transported by the conveyor 101 in the transport route of the conveyor 101. As described above, the posture of the workpiece W on the endless belt 109 is recognized based on the imaging result from the imaging device 11.

In the posture control step S <b> 2, the hand unit 39 is controlled to a posture to be taken when the workpiece W on the endless belt 109 is gripped based on the recognized posture of the workpiece W.
Next, in the gripping step S <b> 3, the work W is gripped by the hand part 39 by the pair of finger parts 43 sandwiching the work W.
In the holding force confirmation step S4, the holding force of the work W in the hand unit 39 is confirmed. At this time, when the holding force of the work W in the hand part 39 is insufficient, the conveyance with respect to the work W is stopped, and the process returns to the imaging step S1.
In the holding state recognition step S5, the holding state of the workpiece W in the hand unit 39 is recognized.
In the transport step S6, by controlling the driving of the arm device 7 and the hand device 9 according to the recognized holding state, the work W is moved to a place different from the conveyor 101 at the transport speed according to the holding state. Transport.

In the present embodiment, after the hand unit 39 grips the workpiece W (after the gripping step S3) and before transporting the gripped workpiece W to a place different from the conveyor 101 (before the transporting step S6). The holding force confirmation step S4 for confirming the holding force of the work W in the hand unit 39 is performed.
In the holding force confirmation step S4, the holding force of the workpiece W in the hand portion 39 is confirmed by swinging the hand portion 39 while holding the workpiece W between the pair of finger portions 43.
In the holding force confirmation step S4, first, the CPU 63 shown in FIG. 3 outputs a drive command for the motor 77 to the motor control unit 91. The motor control unit 91 controls driving of the motor 77 based on a command from the CPU 63. By this control, as shown in FIG. 6A, the hand unit 39 is swung up with the joint portion 47 as a fulcrum while the work W is held between the pair of finger portions 43.

Next, the CPU 63 outputs a reverse drive command for the motor 77 to the motor control unit 91. The motor control unit 91 controls driving (reverse driving) of the motor 77 based on a command from the CPU 63. By this reverse driving, as shown in FIG. 6B, the hand portion 39 is swung down toward the endless belt 109 of the conveyor 101 with the joint portion 47 as a fulcrum. At this time, the motor control unit 91 stops (brakes) the driving of the motor 77 at the timing when the hand unit 39 is swung down toward the endless belt 109.
Thereby, the workpiece W held in an unstable state between the pair of finger portions 43 can be dropped from the pair of finger portions 43. For this reason, it can avoid moving to conveyance step S6 in the unstable holding state which the workpiece | work W falls from the hand part 39 by the operation | movement which swings down the hand part 39. FIG. As a result, it is possible to easily improve the efficiency of work related to conveyance.

  In the holding force confirmation step S4, it is preferable to apply a centrifugal force to the workpiece W when the motor 77 is driven in reverse. Thereby, the workpiece W held by the hand unit 39 in an unstable state can be easily dropped from the hand unit 39. At this time, it is preferable to apply a centrifugal force in a direction intersecting the direction in which the pair of finger portions 43 are arranged, that is, the direction in which the workpiece W is sandwiched. Accordingly, it is possible to make it difficult for a force against the centrifugal force to act on the workpiece W, so that the workpiece W can be easily dropped from the hand portion 39. In the present embodiment, the centrifugal force can be applied in a direction intersecting the direction in which the workpiece W is sandwiched by the swinging shown in FIG.

Further, at this time, it is preferable that the centrifugal force acting on the workpiece W includes the centrifugal force acting in the direction in which gravity acts. As a result, centrifugal force and gravity can be applied to the workpiece W. As a result, the workpiece W held by the hand unit 39 in an unstable state can be more easily removed from the hand unit 39. In the present embodiment, centrifugal force and gravity can be applied to the workpiece W by the swinging shown in FIG.
At this time, as shown in FIG. 6B, it is preferable to apply gravity in a direction intersecting the direction in which the pair of finger portions 43 are arranged, that is, the direction in which the workpiece W is sandwiched. Thereby, it is possible to make it difficult to apply a force against the gravity to the workpiece W, so that the workpiece W can be easily dropped from the hand portion 39.
When the workpiece W has dropped from the hand unit 39 in the holding force confirmation step S4, the process returns to the imaging step S1, and the process is resumed from the imaging step S1. The workpiece W dropped from the hand unit 39 falls on the endless belt 109 of the conveyor 101 and is then collected by the feeder 103 via the conveyor 105.

When the work W has not dropped from the hand unit 39 in the holding force confirmation step S4, the process proceeds to the holding state recognition step S5.
Here, in the present embodiment, the behavior of the hand unit 39 is detected by the angular velocity sensor 51 in the holding force confirmation step S4.
Here, the behavior is a concept indicating the relative motion of the object with respect to the environment, regardless of linear motion or non-linear motion, such as constant velocity motion, acceleration / deceleration motion, and vibration that is reciprocal motion.
The CPU 63 outputs a detection command to the sensor control unit 95 when outputting a reverse drive command for the motor 77 to the motor control unit 91. The sensor control unit 95 causes the angular velocity sensor 51 to detect the angular velocity based on a command from the CPU 63. Thereby, the behavior of the hand unit 39 when the hand unit 39 is swung down toward the endless belt 109 can be detected. At this time, it is preferable to detect at least a behavior including residual vibration of the hand unit 39 when the hand unit 39 is swung down.

Here, when the work W is held in the hand part 39 in an unstable state and in the case where the work W is held in the hand part 39 in a stable state, the behavior when the hand part 39 is driven. Is different.
When the workpiece W is held by the hand unit 39 in a stable state, the angular velocity θv of the hand unit 39 oscillates at a period of t1, centering on 0 degree / sec, as shown in FIG. 7A. It shows the behavior.
On the other hand, when the workpiece W is held by the hand unit 39 in an unstable state, the angular velocity θv of the hand unit 39 is, for example, at a period t2 different from t1 as shown in FIG. May vibrate. In addition to this, as the behavior of the angular velocity θv of the hand unit 39 when the work W is held in an unstable state, for example, vibration amplitude, damping ratio, damping rate, and damping time May be different from the stable state. From such a difference in behavior, an unstable holding state and a stable holding state can be distinguished.

That is, in this embodiment, the unstable holding state and the stable holding state can be determined from the result of detecting the behavior of the hand unit 39 by the angular velocity sensor 51. Thereby, the holding state of the workpiece W can be recognized based on the result of detecting the behavior of the hand unit 39 by the angular velocity sensor 51.
In this way, in the holding state recognition step S5, the holding state of the workpiece W is recognized. The holding state of the workpiece W is recognized by the CPU 63.
And CPU63 controls the conveyance speed of the workpiece | work W in conveyance step S6 according to the holding | maintenance state of the workpiece | work W recognized by holding | maintenance state recognition step S5. Thereby, the conveyance according to the holding | maintenance state of the workpiece | work W can be performed.

In the present embodiment, when the workpiece W is held in the hand unit 39 in an unstable state, the CPU 63 slows the conveyance speed of the workpiece W according to the holding state. Accordingly, it is possible to easily suppress the position and posture of the work W with respect to the hand unit 39 from being shifted or the work W from dropping from the hand unit 39 in the conveyance process. As a result, the work after the transport step S6 including the transport step S6 can be made difficult to be delayed, so that the efficiency of the work can be easily improved.
On the other hand, when the workpiece W is held by the hand unit 39 in a stable state, the CPU 63 increases the conveyance speed of the workpiece W according to the holding state. Thereby, the time taken for conveyance can be shortened. As a result, the time required for the transport step S6 can be easily shortened, so that the work efficiency can be easily improved.

In the present embodiment, the hand part 39 corresponds to the holding part, the pair of finger parts 43 corresponds to the pair of clamping parts, the gripping step S3 corresponds to the holding step, and the holding force confirmation step S4 corresponds to the driving step. ing.
In the present embodiment, in the holding force confirmation step S4, it is adopted that the hand unit 39 is swung as the driving of the hand unit 39 that is performed in order to confirm the holding force of the work W in the hand unit 39. . However, the driving method of the hand unit 39 is not limited to this. As a driving method of the hand unit 39, the rotation of the hand unit 39 by the rotating device 37, the lifting and lowering driving of the hand unit 39 by the lifting device 33, the swinging of the hand unit 39 by the second arm 23, and the hand by the first arm 21. Oscillation of part 39 can also be employed.
Further, as a driving method of the hand unit 39, swinging by the swinging device 35, rotation driving by the rotating device 37, lifting drive by the lifting device 33, swinging by the second arm 23, and swinging by the first arm 21 are performed. A combination of two or more of them can also be employed.
In this embodiment, a scalar type robot is exemplified, but the type of the robot 1 is not limited to this, and various types such as a six-axis robot can be adopted.

  DESCRIPTION OF SYMBOLS 1 ... Robot, 7 ... Arm apparatus, 9 ... Hand apparatus, 10 ... Transfer system, 11 ... Imaging apparatus, 21 ... 1st arm, 23 ... 2nd arm, 25 ... Joint part, 27 ... Joint part, 31 ... Lifting axis 33 ... Elevating device, 35 ... Oscillating device, 37 ... Rotating device, 39 ... Hand part, 43 ... Finger part, 47 ... Joint part, 51 ... Angular velocity sensor, 61 ... Control part, 63 ... CPU, 65 ... Drive control , 67 ... Memory unit, 71 ... Motor, 73 ... Motor, 75 ... Motor, 77 ... Motor, 79 ... Motor, 81 ... Motor, 87 ... Posture image data, 89 ... Hand posture information, 91 ... Motor control unit, 93 DESCRIPTION OF SYMBOLS ... Imaging control part, 95 ... Sensor control part, 101 ... Conveyor, 103 ... Feeder, 105 ... Conveyor, W ... Workpiece | work.

Claims (8)

A holding step for holding the workpiece in a holding unit for holding the workpiece;
A driving step for driving the holding unit in a state where the workpiece is held by the holding unit;
A holding state recognition step for recognizing a holding state of the workpiece by the holding unit, based on a result of detecting an action of the holding unit by the inertial sensor when the holding unit is driven in the driving step;
After the holding state recognition step, driving the holding unit to transfer the work held by the holding unit, and
In the transport step, a transport speed for transporting the workpiece is controlled according to the holding state recognized in the holding state recognition step.
The conveyance method characterized by the above-mentioned. In the holding state recognition step, the holding state is recognized based on a result of detecting the behavior of the holding unit when the driving of the holding unit is stopped by the inertial sensor.
The conveying method according to claim 1. The inertial sensor is an angular velocity sensor that detects angular velocity,
In the holding state recognition step, the angular velocity sensor detects the angular velocity of the holding portion as the behavior of the holding portion,
The conveying method according to claim 1 or 2, wherein In the driving step, the holding unit is swung by driving a swinging device that swings the holding unit.
The conveyance method according to any one of claims 1 to 3, wherein In the driving step, the holding part is swung in a direction including at least a direction in which gravity acts,
The conveying method according to claim 4. A holding unit for holding the workpiece;
An inertial sensor provided in the holding part;
A control unit for controlling the driving of the holding unit,
The control unit causes the holding unit to hold the workpiece, detects the behavior of the holding unit when the holding unit is driven, and detects the behavior of the holding unit based on the detection result of the inertia sensor. Recognizing the holding state of the workpiece, and controlling the conveyance speed in conveying the workpiece according to the holding state;
A robot characterized by that. A rocking device for rocking the holding portion;
The control unit detects a behavior of the holding unit when the holding unit is swung by the swinging device by the inertia sensor, and based on a result detected by the inertia sensor, the control unit detects the behavior of the work by the holding unit. Recognizing the holding state and controlling the transfer speed in transferring the workpiece according to the holding state;
The robot according to claim 6. The control unit swings the holding unit in a direction including at least a direction in which gravity acts.
The robot according to claim 7.

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